George w



GLW. WHITE.

ROTARY CYLINDER FURNACE.

Patented'oct. 4,1881.

Witnesses UNITED STATES PATIENT OFFICE.-

GEORGE W. WHITE, OF SAN FRANCISCO, CALIFORNIA.

ROTARY-CYLINDER FURNACE.

SPECIFICATION forming part of Letters Patent No. 248,000, dated October 4, 1881. Applicationfiled August 24, 1877.

To all whom it may concern Be it known that I, GEORGE W. WHITE, of the city and county of San Francisco, and State of California, have invented Improvements in Rotary-Cylinder Furnaces; and I do hereby declare the following to be a full, clear, and exact description thereof, reference being bad to the accompanying drawings.

My invention relates to certain improvements upon therotary-cylinder furnace for which Letters Patent No. 44,145, dated September 6, 1864, and No. 46,287, dated Febru-' and drop the ore through the passing heat, the

whole forming a simple and complete system for roasting ores. In the first-named patent above referred to the fire-place or furnace was placed at the upper or receiving end of the cylinder and the ore passed down the incline in the same direction that the heat and products of combustion traveled, while in the latternamed patent the furnace or fire-place was located at the lower end of the cylinder and the ore was introduced at the upper end, so that the ore was compelled to travel against the heat. The latter furnace was constructed with a central flue, through which the heat and products of combustion passed, and a series of parallel fines surrounding the central flue, through which the ore passed in being reduced.

My presentinvention consists, first, of an arrangement by which I\am enabled to shift the furnace to either inclination and feed the ore adapts it for reducing that class of ores from U which it is desired to expel metallic vapors,

and from which it is desired to exclude the products of combustion during the reducing process.

Referring to the accompanying drawings, Figure 1 is a perspective of a furnace with my improvements attached. Fig. 2 is a sectional View through zz of Fig. 4. Fig. 3 is a section on liney y of Fig. 4. Fig. '4 is a longitudinal section of the furnace.

In my present construction of the furnace I mount the cylinder A, fire-place or furnace B, and receiving-box 0 upon a single platform, D. The furnace or fire-place B is placed at one end of the platform and the receiving-box O at the opposite end, while the rotating cylinder A is mounted upon suitable supportingpulleys between them, so that its ends pass through openings in their sides, as represented. A feed-hopper, E, is placed upon the furnace B, and a conducting-tube,f, extends from its lower end downward into the open end of the cylinder. Another hopper, Gr, is placed above the receiving-chamber O, at the opposite end of the cylinder, and atube, h, connects its lower end with the interior of the inner cylinder, so that the ore can be fed to either end of the cylinder, as desired.

11 is the chimney or flue through which the draft from the fire-place B passes ontinto the open air. This chimney-fine is made large enough around the inner cylinder, K, to prevent being chokcd. The inner cylinder, K, of my present furnace projects beyond the outer cylinder and outer flues, l, at the end next to the chamber (J. The outer flues are thus made toopen into the chimney flueb, through which the draft from the fire passes into the open air,

while the ore is carried by the elongation of the central line, K, across the chimney and emptied into the receiving-chamber Owithout coming in contact with the draft from the firefurnace. This is an important feature of the furnace, as among other evils existing in ordinary furnaces for roasting pulverized ores, the products of combustion and draft from the fire-places pass through the ore-roastin g chambers, and the draft is necessarily so strong that it carries with it a large percentage of the most ICC finely pulverized ore. As the ore is roasted when it enters the receiving-chamber 0 it is evident that the chamber 0 may be a mere open uninclosed space. It is enough that the central ore-flue, K, carries the ore beyond the chimney, so that the ore will be roasted and deposited without coming in contact with the draft, and products of combustion which come from the fire-furnace B pass through the outer flue, I, and out of the chimney I).

The platform I) has a V-shaped ridge, 1', across its middle on its under side, and this ridge rests upon and is secured to a sub-platform, J, so that the entire furn ace can be tilted upon this ridge to incline in either direction, according to the direction in which it is desired to feed the ore through the cylinder, or

it. may be mounted upon trnnnions, as most convenient.

The cylinder A is constructed with a large central flue or passage, K, and aseries of surrounding fiues or passages, 1. To make this cylinder, I take two concentric cylinders, the

outer one of which forms the main or outside cylinder, while the inner one is considerably smaller in diameter than the outer one. This inner cylinder I support in position by means of parallel partitions m, which extend longitudinally the entire length of the cylinders and between'them, so that the space between each two partitions will form a heat flue or passage; or the inside cylinder may be made in longitudinal sections and secured in position by any suitable means.

In my former patents I described and claimed a plan of constructing the interior of the cylinder with longitudinal ridges, projections, or ribs placed at intervals apart, which ridges, projections, or ribs served to alternately raise and drop the ore as the cylinder rotated.

The usual manner of forming the ridges, projections, or ribs was to form alining of firebrick on the inside of the cylinder, and place everythird or fourth rowof bricks endwise, so as to form the projections described. In applying this inside cylinder to one of those old furnaces, therefore, I can simply place the inside cylinder inside of these projecting rows, so that they will form the partitions and outside passages or flues. The inside cylinder I provide with longitudinal ribs, projections, or recesses 0, for lifting and dropping the ore in the same manner as when a single cylinder is used. In this furnace the ore will be fed into the central or main flue, while the heat and products of combustion enter and pass through the surrounding fines or passages, thus heating up the ore-flue without direct contact of the flame with the ore.

By this method a much better concentration of heat upon the ore is obtained, and at a less cost of fuel, than when the heat passes through the central flue and the ore through the outer flues. The operation of one large central flue for the treatment of the ore is also much superior to the combined operation of the series of ore-fines shown in my former patent.

By this construction I obtain a furnace possessing the following advantages:

First. By tipping the furnace, ore may be fed through it, so as to pass while being reduced in the same direction that the heat passes, or in the opposite direction, as may be desired, and as may be best for the particular quality of ore being treated.

Second. The fire and heat surrounds the main flue in which the ore is treated, and thereby furnishes a better heat with less fuel than can be obtained in rotary furnaces not so constructed.

Third. The draft and products of combustion do not pass through the main fine or in contact with the ore.

I am aware that in the process of Charles William Siemens for manufacturing cast-steel a rotary furnace was used in combination with a melting-furnace, and that such rotary furnace had a double series of concentric tubes running parallel with a main central flue, through which the ore passed; but in that rotary furnace the series of concentric fines did not open into a fire-chamber, but were of a peculiar construction and combination for the purpose of utilizing gases arising from the redueing process and hot air. These only supplied a small part of the heat for the furnace. The principal heat was obtained by burning fuel mixed with the ore in the central flue. The main fire being in the central flue where the ore was being roasted necessitated the passing of a draft through that flue, which is not done in my furnace.

Having thus described my invention, what I claim, and desire to secure by Letters Patcut, is-

1. The rotary cylinder A, furnace B, and receiving-box G, in combination with the platform having a central bearing, whereby they can be tilted to either inclination, substantially as set forth.

2. The combination, in a rotary-cylinder furnace, ot' the outside cylinder, A, provided with its flues l, and the inside .cylinder, K, provided with open ends, with the furnace B, constructed as described, chamber 0, and duplex feeding devices E G, whereby the ores are made to pass in either direction through a central rotating fine, while the heat and pro duct of combustion are conducted through flues or passages which surround the ore-flue, and out of contact with the ore, as set forth.

3. In a rotary-cylinder furnace, the combination of a central ore-flue with a series of concentric fire-fines, through which the draft and products of combustion pass from the fireplace to the chimney 1) direct without comingin contact with the ore, all constructed and operating substantially as herein described.

4. In a rotary-cylinder furnace, the combination of an extended inner ore-cylinder and ore-receivin gchamber, G,with theshorter outer concentric lines, I, and the draft-chimney b, constructed and operating substantially as herein described.

a 5. The combination of the fire-furnace B, the ore being roasted will not come in contact with rotating'cylinder IA, having the central orethe draft or products of combustion from the flue, K,the fire and draft fines Z, with the refire-place B, substantially as herein described.-

ceiving-chamber O, and chimney b, all con- In witness whereof I have hereunto set my 5 structed and operating substantially as herein hand and seal. described i GEO W WHITE [L s 6. The combination, in a rotary-cylinder furnace, of the firefurnace B, the outeracon- Witnesses: centric lines, I, the chimney b, and the central OLWYN T. STACY;

1o ore-chamber, K, with afeeding device, that the FRANK A. BROOKS. 

